Stairs or steps are frequently covered by a stair covering which may cover the surface of each stair tread and which may also cover the vertical surface of the stair riser. In one form of stair edge profile assembly for use in such a situation, the assembly comprises a tread angle member having a tread limb portion whose free end forms a cover blade portion for extending over a covering on the stair tread. Arranged on the tread angle member at a right angle thereto is an abutment limb, while the assembly further comprises a base profile member which can be fixed on the stair. Such an arrangement is to be found for example in U.S. Pat. No. 4,455,797 in which the base profile member is fitted in a L-shape around the stair edge and fixed to the stair by means of a nail. At the stair edge the base profile member has an inclined surface serving as an abutment contact surface for the tread angle member. The outsides of the base profile member and the inside of the tread angle member fit together in positively locking relationship. The tread angle member is made from plastic material and has air chambers therein in order to improve the damping properties of the assembly. Provided on the tread angle member at both ends thereof are so-called cover blade portions which, after the tread angle member has been fitted on to the base profile member on the stair, press the tread covering against the base profile member. Use of this assembly is restricted to carpets which are compressed and clamped in position between the cover blade portion and the base profile member.
A disadvantage of this construction is also the consideration that use thereof is restricted to stair coverings of a quite specific thickness of material. When laying for example carpeting of a greater thickness or when using laminate or parquet floor coverings, a different tread angle member has to be used for each specific thickness of material.